Nanotube structures such as carbon nanotubes are used for a variety of applications. Carbon nanotubes can be formed by chemical synthesis. The result, however, is a mixture of semiconducting and metallic carbon nanotubes.
The composition of nanotubes formed from a semiconductor such as silicon (Si) or silicon germanium (SiGe) can be controlled. However, with the techniques typically employed to fabricate semiconductor nanotubes such as chemical vapor deposition (CVD) or a gas phase condensation it is very difficult to achieve nanotubes with dimensional uniformity and alignment.
Therefore, improved techniques for forming semiconductor nanotubes would be desirable.